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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter B-152

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

March 27, 2008

In Reply Refer To: HSSD/B-151

Bryant L. Lowery, P.E.
Special Design Engineer
Location and Design Division
Virginia Department of TransportationM
1401 East Broad Street
Richmond, Virginia 23219

Dear Mr. Lowery:

This letter is in response to your request for Federal Highway Administration (FHWA) acceptance of a roadside safety device for use on the National Highway System (NHS).

Name of device:Permatile Precast Concrete Barrier 10 foot length
Type of device: Portable concrete barrier
Test Level:NCHRP Report 350 TL-3
Prior Testing conducted by:Texas Transportation Institute (TTI)
Date of request:March 14, 2008

You requested that we find this device acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”

Requirements

Roadside safety devices should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features". FHWA Memorandum “Action: Identifying Acceptable Highway Safety Features” of July 25, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

Description

You requested formal acceptance of the Virginia Department of Transportation (VDOT) 10 foot F-shape Concrete Barrier with the pin and loop positive connection. A 20 foot version of this design (Scan01.tif, enclosed for reference) was tested and accepted for use as a TL-3 NCHRP 350 temporary barrier in FHWA Acceptance Letter B-54 dated May 18, 1999. Permatile Concrete Products Company manufactured and supplied this barrier that was tested by TTI under NCHRP report 350 Test 3-11, Contract No. T99011 and Project No. 402041. The drawings “Scan02.tif” and “Scan03.tif” include the details of the 10' version and are enclosed for reference.

Crash Testing

The 20-foot long version of the VDOT barrier was successfully crash tested as noted above. Through the observation of crash testing of numerous portable concrete barrier segments of varying lengths over the years FHWA has learned that the length of the barrier plays little, if any, role in the successful performance. As long as the steel reinforcing and the integrity of the end connections are maintained, the shorter barrier length will be acceptable for use.

Findings

The 10-foot long VDOT barrier described above and detailed in the enclosed drawings is acceptable for use on the NHS under the range of conditions that the 20-foot barrier was tested, when proposed by a State.

Please note the following standard provisions that apply to FHWA letters of acceptance:

 

Sincerely yours,

David A. Nicol

David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety

2 Enclosures

Page last modified on August 16, 2011.
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